A teeth whitening device generates radicals that act on the pigment molecules of teeth and supplies the radicals to the teeth to whiten the teeth. For example, a dentist uses a medical teeth whitening device. The medical teeth whitening device irradiates oxygen bleach with ultraviolet rays or heats oxygen bleach to generate radical species from the oxygen bleach. The ultraviolet ray irradiation or heating is performed while supplying oxygen bleach into the oral cavity. Thus, irradiation of ultraviolet rays or heating may damage the teeth or gum.
A home-use teeth whitening device, which generates radical species without using oxygen bleach, is used in view of such influence on the teeth or gum. For example, Patent Document 1 discloses a teeth whitening device that includes a gas cylinder, which stores gas that generates plasma, a plasma generation cell, which generates plasma containing radical species that are active ingredients from the gas of the gas cylinder, an applicator tube, which includes a plasma discharge port, and a hose, which connects the plasma generation cell and the applicator tube.
The user of the teeth whitening device drives the plasma generation cell while holding the applicator tube so that the plasma discharge port is directed toward the teeth that are subject to whitening. The generated plasma is supplied to the teeth through the applicator tube.